TCT+, eTCT and I-DLTS measurement setups at the CERN SSD Lab

Christian Gallrapp1

M. Bruzzi2 ,M. Fernandez3, C. Figueiredo1, M. Moll1, H. Neugebauer1,4

1CERN / 2INFN, University of Florence3IFCA-Santander/ 4University of Hamburg

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TCT Setups in the CERN SSD Lab

• I-DLTS setup based on former TCT setup• eTCT setup • TCT+ setup combines TCT and eTCT

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I-DLTS setup

TCT+ setup

eTCT setup

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Current-Deep Level Transient Spectroscopy (I-DLTS)

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I-DLTS setup• Equipment

– Huber CC505 chiller Temperature controlled (PT100)Minimum Temperature on the sample ca. -25C

– μs-pulsed LASER• Red (660nm)• IR (1064nm)

– Optics for red and IR illumination from top and bottom

– Temperature measurement on the DUT (PT1000 with Keithley 2410)

– Bias voltage up to 1000V– Bias Tee (Vmax = 200V)– Shielded Box (Louvain-Box)– Agilent Scope (2.5GHz Bandwidth)– Reference diode for red and IR

• LabView based software to loop parameters– temperature, bias voltage, pulse width, pulse intensity and repetition

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I-DLTS

• Motivation– Improve understanding of charge carrier detrapping

for defect characterization – Investigate energy levels and cross-section of detrapping centers

• Previous work:– G. Kramberger, et. al.; 2012 - JINST 7 P04006

Determination of detrapping times in semiconductor detectors – M. Gabrysch, et.al.; 2012 - 21st RD50 Workshop

Charge carrier detrapping in irradiated silicon sensors after microsecond laser pulses

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I-DLTS Layout

• Illumination with μs-pulsed red and IR LASER pulses (> 0.5μs)• Biasing up to 200V with maximum bandwidth (20kHz - 10GHz)• No amplifier to keep maximum bandwidth• Temperature controlled (> -25C)• Scope with upper bandwidth limit 2.5GHz09/05/2014

μs - pulsed LASER (red, IR)Front and back side illumination200Hz trigger frequency

Bias Tee

HV Power Supply

Scope 2.5GHz

DUT

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Samples and Parameter Space• Parameter space

– Temperature• -20C to 20C in 5C steps

– Voltage• 50V, 100V, 150V, 200V

– Pulse width• 1us, 2us, 3us, 4us, 5us

– LASER Intensity• 1.7V, 1.8V, 1.9V, 2.0V

– Repetition: • Five repetitions for each scan point

• Micron Samples:– Thickness: 300μm– FZ and MCz n-in-p– Irradiation at CERN PS:

24GeV/c protons– Fluence:

non irrad; 5×1013 p/cm2 ; 5 ×1014 p/cm2 ; 1 ×1015 p/cm2

• Illumination: Red front

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• Further measurements: – Scan parameter space with IR front, Red and IR back– Determination of most suitable parameter space for analysis

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Current with Temperature

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-25C -10C

5C 20C

FZ n-in-p 1×1015 p/cm2 at 200VIntensity 2V

• Signal height after LASER pulse varies between 0mV at -25C and -1mV at 20C• Current drop during pulse varies with temperature (also voltage)

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Double Boxcar

09/05/2014D. Lang; 1974 - J. Appl. Phys. 45 Deep level transient spectroscopy: A new method to characterize traps in semiconductors‐

• Select rate window defined by t1 and t2

• Determine signal variation Signal(t1)-Signal(t2) for different temperatures

• Operation modes– t1 fixed, vary t2

– t2 fixed, vary t1

– t1/t2 fixed, vary t1 and t2

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Box Plot for variable pulse width

• t1 fixed, 200ns after pulse• vary t2

– Box width: 1μs, 2μs, 3μs and 4μs

• Box plot varies with LASER pulse width

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1μs pulse 3μs pulse

5μs pulse

FZ n-in-p 5 ×1014 p/cm2 at 200VIntensity 2V

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Next Steps• Influence of electronics on

signal– Undershoot in unirradiated

sample– Undershoot visible at low

temperatures (low de-trapping)• Analysis following approach for TCT pulses

(see: Kramberger, 2012 - JINST 7 P04006 )• Simulation– transient after laser pulse– Current drop during laser pulse

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Edge-TCT

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eTCT setup• Equipment

– Computer controlled Peltier cooling (PT1000)Min. Temperature on the DUT -20C

– Annealing up to 60C directly in the setup– picosecond-pulsed IR LASER– Optics to illuminate the sample edge– Bias voltage up to 1000V– Wide bandwidth amplifier– Bias Tee for DC readout – EM shielded Box– Agilent Scope (2.5GHz Bandwidth)– XYZ stages with μm step width

• LabView based software to loop parameters– temperature, bias voltage and position

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Recent eTCT measurements

• eTCT measurements on HV-CMOS– D. Muenstermann, et.al.; 2013 –

23rd RD50 Workshop Active pixel sensors in 180 nm HV CMOS technology for HL-LHC detector upgrades

• Irradiated Micron strip sensors– S. Wonsak, et.al.;

2014 – 24th RD50 Workshop Status of Silicon Strip Sensor Measurements at Liverpool

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TCT+ a common setup for TCT and eTCT

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TCT+ Setup• Equipment

– Computer controlled Peltier cooling (PT1000) with Huber CC505 chillerMin. Temperature on the DUT -20C

– picosecond-pulsed LASER• Red (660nm)• IR (1064nm)

– Optics for illumination• Top red and IR• Bottom red and IR• Sample edge IR

– Bias voltage up to 1000V– Wide bandwidth amplifier– Bias Tee for AC readout – EM shielded Box– Agilent Scope (2.5GHz Bandwidth)– XYZ stages with μm step width

• LabView based software to loop parameters– temperature, bias voltage, position and repetition

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TCT+ Layout• Combination of a conventional red and IR TCT setup with an

edge-TCT setup • Temperature controlled Peltier/Chiller cooling system.• Stage system provides μm steps in X, Y and Z

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IR (1064nm)

Red (660nm)

Pulsed laser with a trigger frequency of 200Hz

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• Irradiated MCz diodes (70MeV protons)

• R. Carney – Master Thesis; University of EdinburghInvestigation of Magnetic Czochralski diodes using novel TCT setup for future silicon detectors

Measurements with TCT+Irradiated MCz diodes

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Φ = 1 ×1013 neq/cm2

Φ = 5 ×1014 neq/cm2

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Measurements with TCT+Diodes with amplification

• V. Greco , et.al.; 2014 – 24th RD50 Workshop Preliminary results on proton irradiated LGAD PAD detectors

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Bias = 50V Bias = 150V Bias = 150V

Surface scan with red LASER front

Voltage scan with red LASER back

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Measurements with TCT+3D strip diodes

• Single sided 3D strip diodes on SOI from CNM

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Surface scan with IR LASER at 70V Surface scan with red LASER at 70V

columns columns

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Measurements with TCT+irradiated strip sensors from Micron

• TCT and eTCT on 1×1015 neq/cm2

irradiated strip sensors– S. Wonsak, et.al.;

2014 – 24th RD50 Workshop Status of Silicon Strip Sensor Measurements at Liverpool

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Q(z,V) eTCT

Q(x,V) IR top

eTCT

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Upcoming measurement

• Irradiated Micron diodes 24GeV/c protons (FZ, MCz)– non-irrad., 5.9×1013 p/cm2 , 1.0×1014 p/cm2 ,

5.3×1014 p/cm2 , 9.8×1014 p/cm2 , 2.0×1015 p/cm2 , 4.4×1016 p/cm2

• Irradiated Micron strip sensor 24GeV/c protons (FZ, MCz)– non-irrad., 6.9 ×1014 p/cm2, 9.7 ×1014 p/cm2,

1.9 ×1015 p/cm2, 3.1 ×1016 p/cm2

• Pion irradiated STMicroelectronics diodes– non-irrad., 1×1011 π/cm2, 3×1011 π/cm2,

1×1012 π/cm2, 3×1012 π/cm2,1×1013 π/cm2, 3×1013 π/cm2,1×1014 π/cm2, 3×1014 π/cm2, 7×1014 π/cm2

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Thanks for your attentionQuestions?

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